The Thin Film Transistor Liquid Crystal Display (TFT-LCD) technology, as a mainstream display manufacturing technology at present, has been widely applied. With the continuous improvement of the manufacturing technology, the resolution of liquid crystal displays becomes higher and higher, from high definition (1366×768) very popular in the past to full high definition (1920×1080), to 4K2K (3840×2160) TV sets currently popular with consumers and even 8K4K (7680×4320) TV sets to be launched in the future.
The improvement of the resolution of liquid crystal displays implies that the pixel unit becomes smaller and smaller, the difficulty in design and manufacture becomes lager and larger and the distance between various wirings also becomes smaller and smaller. Consequently, various problems, one of which is the dark fringe of pixels, are caused.
The dark fringe of pixels refers that an opening region in a pixel unit close to a via hole is non-transmittable to light normally during the normal display of a liquid crystal panel. As shown in FIG. 1, a structural diagram a main region of a pixel unit in the prior art is shown. The pixel unit includes a plurality of electrodes and a pad 20. The pixel electrodes include a plurality of oblique pixel electrodes 11 extending obliquely and transverse pixel electrodes 12 extending transversely. The pad 20 is covered on a via hole 30. An opening region is formed on the pixel electrodes at a position close to the via hole 30. As the pixel unit is small, the pad 20 accesses to the opening region and is partially overlapped with projections of the oblique pixel electrodes 11, so that the pad 20, the transverse pixel electrodes 12 or other conductive components cause an interference to the electric field of the oblique pixel electrodes 11. As shown in FIG. 1a, a simulated effect diagram of the penetration rate of the main region of the pixel unit simulated by Expert LCD software is shown, where grey white indicates that it is light-transmittable while black indicates that it is not light-transmittable, and there is dark fringe in the opening region marked by a circle.
As shown in FIG. 2, a structural diagram of a sub region of a pixel unit in the prior art is shown, where a common electrode 40 of the pixel unit accesses to the opening region, and the common electrode 40 is partially overlapped with projections of oblique pixel electrodes 11, so that the common electrode 40, the transverse pixel electrodes 12 or other conductive components cause an interference to the electric field of the oblique pixel electrodes 11. As shown in FIG. 2a, a simulated effect diagram of the penetration rate of the sub region of the pixel unit simulated by Expert LCD software is shown, where grey white indicates that it is light-transmittable while black indicates that it is not light-transmittable, and there is dark fringe in the opening region marked by a circle.
Therefore, an electric field around the opening region of the pixel electrode in the prior art will have an impact on the electric field of oblique pixel electrodes, there resulting dark fringe in the opening region. The occurrence of the dark fringe will directly decrease the aperture ratio of pixels and the penetration rate of a panel, and may additionally cause uneven display brightness problems, thereby degrading the quality of display.